The phenotypic expression of a transgene in a plant is determined both by the structure of the gene itself and by its location in the plant genome. At the same time the presence of the transgene (in a foreign DNA) at different locations in the genome will influence the overall phenotype of the plant in different ways. The agronomically or industrially successful introduction of a commercially interesting trait in a plant by genetic manipulation can be a lengthy procedure dependent on different factors. The actual transformation and regeneration of genetically transformed plants are only the first in a series of selection steps, which include extensive genetic characterization, breeding, and evaluation in field trials, eventually leading to the selection of an elite event.
Cotton fiber is the single most important textile worldwide. About 80 million acres of cotton are harvested annually across the globe. Cotton is the fifth largest crop in the U.S. in terms of acreage production, with over 15 million acres planted in 2000. Primary weed species for cotton are Ipomoea sp. (morning glory), Amaranthus spp. (pigweed), Cyperus spp. (nutsedge), Xanthium spp. (cocklebur) and Sorghum spp. (johnsongrass). Before the introduction of broad-leaf herbicides that could be used on a growing cotton field, growers used directed, post-emergence applications of nonselective herbicides taking care not to contact the growing crop plants. As this requires a difference in height between the weeds and the crop, this is not always possible. Especially for small cotton, this practice is time-consuming and potentially damaging to the crop.
The unequivocal identification of an elite event is becoming increasingly important in view of discussions on Novel Food/Feed, segregation of GMO and non-GMO products and the identification of proprietary material. Ideally, such identification method is both quick and simple, without the need for an extensive laboratory set-up. Furthermore, the method should provide results that allow unequivocal determination of the elite event without expert interpretation, but which hold up under expert scrutiny if necessary. Specific tools for use in the identification of elite event EE-GH3 in biological samples are described herein.
EE-GH3 has been identified as an elite event from a population of transgenic cotton plants in the development of cotton (Gossypium hirsutum) resistant to the herbicide N-phosphonomethylglycine and salts thereof, also known as glyphosate. The transgenic cotton plants contained a chimeric gene conferring tolerance to glyphosate, comprising a modified epsps gene from Zea mays encoding glyphosate tolerant 5-enol-pyruvylshikimate-3-phosphate synthase (EPSPS) (as described in U.S. Pat. No. 6,566,587) under control of a plant-expressible promoter (as described in U.S. Pat. No. 5,491,288 or U.S. Pat. No. 5,792,930).
Cotton plants comprising a glyphosate tolerance gene have been disclosed in the art. However, none of the prior art disclosures fail to teach or suggest the present invention.